Balfe Motorsport duo Ashley Marshall and Jack Brown picked their way through a chaotic two hours of racing to snatch their maiden British GT4 victories at Spa, as well as McLaren’s first of the season.

Marshall and Brown benefited from a late penalty for the race-leading Newbridge Motorsport Aston Martin to sweep to a breakthrough win after a superb performance while nursing mechanical issues.

The start-line collision not only accounted for a handful of GT3 cars but also hugely affected the GT4 pecking order as cars dodged left and right to avoid the chaos.

Marshall, who started fourth, was initially lucky to get through unscathed and assume an early second place behind Will Burns in the pole-sitting Century Motorsport BMW. But he was then involved in a second collision at La Source, which immediately knocked the tracking out and affected the McLaren’s throttle control.

Regardless, he was able to continue and not only kept the car going but moved it well and truly into contention by hounding Burns for the lead throughout the first half hour, before finally getting a run alongside the M4 into Eau Rouge and sweeping into the race lead on the inside line at Les Combes.

Marshall then got the hammer down in clean air and managed to pull a gap of three seconds over Burns before diving into the pits to hand across to Brown. But, as a Silver Cup pairing, the additional 26s stationary in the pits closed things up and brought other cars into play, specifically the Newbridge Aston of Matt Topham and Darren Turner.

Topham was stone last at the end of the first lap after slamming on the brakes to avoid Abba’s stricken Mercedes-AMG at the start. But once up to speed he enjoyed a controlled stint and repeatedly benefited as rivals hit trouble to run seventh before pitting for Turner. The shorter stop was a huge help to the Aston, and Turner vaulted several cars to re-join in third.

Once installed, Turner took chunks out of those ahead, first passing Katie Milner’s Team Rocket RJN McLaren – which had enjoyed an impressive opening stint in the hands of Harry Hayek who’d hounded Burns before the pit window opened – for second, before then closing in on Brown in the lead McLaren.

Turner lapped up to two seconds faster than the hobbled 570S and eventually made a brave move for the lead around the outside of Pouhon, completing the job into Fagnes.

Things then looked settled until Turner was pinged for track limits offences in the final minutes and given a 30s penalty in lieu of a drive-through. That handed the laurels back to Marshall/Brown, with Turner/Topham retaining second, just ahead of championship leaders Burns and Gus Burton who were delayed by a 20s Success Penalty.

Second overall was also enough for Topham/Turner to secure the Pro-Am class victory.

Matt Cowley came out on top of a tight scrap over fourth in the Academy Motorsport Ford Mustang he shares with Will Moore, the pair just escaping from a tight pack consisting of Andrew Gordon-Colebrooke/Chris Salkeld’s Century BMW and Richard Williams/Sennan Fielding’s Steller Audi R8. Team Rocket RJN’s McLaren of Milner/Hayek was classified sixth despite stopping at the Bus Stop Chicane after a puncture.

The high rate of attrition after the start accounted for many others. Team Rocket RJN’s other McLaren of Michael Benyahia/Alain Valente was heavily damaged off the line, while suspension damage from the incident put Assetto Motorsport’s Ginetta of Mark Sansom/Charlie Robertson out shortly after.

The next to fall victim was Toyota Gazoo Racing UK’s Supra, which had to stop to have a snapped suspension damper replaced. That car would re-join to claim second in the Pro-Am class in the hands of John Ferguson/Scott McKenna. The latter also collected the Sunoco Fastest Lap Award.